(PR109) Evaluation of Mandibular Molar Distal Canal Morphology of a Diverse Military Population, Using Cone-Beam Computed Tomography (CBCT)

Objective: The distal canal of mandibular molars typically exhibits single canal morphology, though the canal's shape and width vary greatly. Current instrumentation protocols may not adequately accommodate this variability, necessitating better understanding of canal morphology and buccal-lingual dimensions. This study aimed to evaluate the distal root canal morphology of first and second molars using CBCT imaging. The secondary aim was to assess the correlation between quality of obturation and presence of apical hypodensity in previously treated teeth.

Methods: 264 mandibular molars were evaluated using a J Morita 3D Accuitomo-170 (4x4 cm FOV, 80 µm voxel size). Variables recorded included patient age, sex, Vertucci classification, orifice shape, number of points-of-negotiation (PON) and portals-of-exit (POE), canal width at the orifice and widest point, and apical foramen directions. For previously treated teeth, missed canals and periapical hypodensity were noted. Statistical analysis performed using SPSS version 25.0 with a significance level set at p<0.05.

Results: Males and younger age were correlated with an increased number of distal POEs. Younger age was also associated with greater canal width. Significant differences were observed between first and second molars in distal PONs, POEs, orifice shape, and canal width. A statistically significant correlation between unfilled canals space and presence of apical hypodensity was observed.

Conclusions: Males and younger patients have more distal POEs, and younger patients have greater canal width. First and second molars differ significantly in canal morphology. Increased prevalence of apical hypodensity with unobturated canal space suggest correlation with poorer outcome.